/*
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 * and open the template in the editor.
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package PWS;

/**
 *
 * @author LBAOMELM
 */
import java.io.File;
import java.util.Hashtable;
import java.util.Enumeration;
import javax.swing.*;
import javax.swing.filechooser.*;

/** 
 * A convenience implementation of FileFilter that filters out 
 * all files except for those type extensions that it knows about. 
 * 
 * Extensions are of the type ".foo", which is typically found on 
 * Windows and Unix boxes, but not on Macinthosh. Case is ignored. 
 * 
 * Example - create a new filter that filerts out all files 
 * but gif and jpg image files: 
 * 
 *     JFileChooser chooser = new JFileChooser(); 
 *     ExampleFileFilter filter = new ExampleFileFilter( 
 *                   new String{"gif", "jpg"}, "JPEG & GIF Images") 
 *     chooser.addChoosableFileFilter(filter); 
 *     chooser.showOpenDialog(this); 
 * 
 */
public class ExtensionFileFilter extends FileFilter {

    private static String TYPE_UNKNOWN = "Type Unknown";
    private static String HIDDEN_FILE = "Hidden File";
    private Hashtable filters = null;
    private String description = null;
    private String fullDescription = null;
    private boolean useExtensionsInDescription = true;

    /** 
     * Creates a file filter. If no filters are added, then all 
     * files are accepted. 
     * 
     * @see #addExtension 
     */
    public ExtensionFileFilter() {
        this.filters = new Hashtable();
    }

    /** 
     * Creates a file filter that accepts files with the given extension. 
     * Example: new ExampleFileFilter("jpg"); 
     * 
     * @see #addExtension 
     */
    public ExtensionFileFilter(String extension) {
        this(extension, null);
    }

    /** 
     * Creates a file filter that accepts the given file type. 
     * Example: new ExampleFileFilter("jpg", "JPEG Image Images"); 
     * 
     * Note that the "." before the extension is not needed. If 
     * provided, it will be ignored. 
     * 
     * @see #addExtension 
     */
    public ExtensionFileFilter(String extension, String description) {
        this();
        if (extension != null) {
            addExtension(extension);
        }
        if (description != null) {
            setDescription(description);
        }
    }

    /** 
     * Creates a file filter from the given string array. 
     * Example: new ExampleFileFilter(String {"gif", "jpg"}); 
     * 
     * Note that the "." before the extension is not needed adn 
     * will be ignored. 
     * 
     * @see #addExtension 
     */
    public ExtensionFileFilter(String[] filters) {
        this(filters, null);
    }

    /** 
     * Creates a file filter from the given string array and description. 
     * Example: new ExampleFileFilter(String {"gif", "jpg"}, "Gif and JPG Images"); 
     * 
     * Note that the "." before the extension is not needed and will be ignored. 
     * 
     * @see #addExtension 
     */
    public ExtensionFileFilter(String[] filters, String description) {
        this();
        for (int i = 0; i < filters.length; i++) {
            // add filters one by one  
            addExtension(filters[i]);
        }
        if (description != null) {
            setDescription(description);
        }
    }

    /** 
     * Return true if this file should be shown in the directory pane, 
     * false if it shouldn't. 
     * 
     * Files that begin with "." are ignored. 
     * 
     * @see #getExtension 
     * @see FileFilter#accepts 
     */
    public boolean accept(File f) {
        if (f != null) {
            if (f.isDirectory()) {
                return true;
            }
            String extension = getExtension(f);
            if (extension != null && filters.get(getExtension(f)) != null) {
                return true;
            };
        }
        return false;
    }

    /** 
     * Return the extension portion of the file's name . 
     * 
     * @see #getExtension 
     * @see FileFilter#accept 
     */
    public String getExtension(File f) {
        if (f != null) {
            String filename = f.getName();
            int i = filename.lastIndexOf('.');
            if (i > 0 && i < filename.length() - 1) {
                return filename.substring(i + 1).toLowerCase();
            };
        }
        return null;
    }

    /** 
     * Adds a filetype "dot" extension to filter against. 
     * 
     * For example: the following code will create a filter that filters 
     * out all files except those that end in ".jpg" and ".tif": 
     * 
     *   ExampleFileFilter filter = new ExampleFileFilter(); 
     *   filter.addExtension("jpg"); 
     *   filter.addExtension("tif"); 
     * 
     * Note that the "." before the extension is not needed and will be ignored. 
     */
    public void addExtension(String extension) {
        if (filters == null) {
            filters = new Hashtable(5);
        }
        filters.put(extension.toLowerCase(), this);
        fullDescription = null;
    }

    /** 
     * Returns the human readable description of this filter. For 
     * example: "JPEG and GIF Image Files (*.jpg, *.gif)" 
     * 
     * @see setDescription 
     * @see setExtensionListInDescription 
     * @see isExtensionListInDescription 
     * @see FileFilter#getDescription 
     */
    public String getDescription() {
        if (fullDescription == null) {
            if (description == null || isExtensionListInDescription()) {
                fullDescription = description == null ? "(" : description + " (";
// build the description from the extension list  
                Enumeration extensions = filters.keys();
                if (extensions != null) {
                    fullDescription += "." + (String) extensions.nextElement();
                    while (extensions.hasMoreElements()) {
                        fullDescription += ", " + (String) extensions.nextElement();
                    }
                }
                fullDescription += ")";
            } else {
                fullDescription = description;
            }
        }
        return fullDescription;
    }

    /** 
     * Sets the human readable description of this filter. For 
     * example: filter.setDescription("Gif and JPG Images"); 
     * 
     * @see setDescription 
     * @see setExtensionListInDescription 
     * @see isExtensionListInDescription 
     */
    public void setDescription(String description) {
        this.description = description;
        fullDescription = null;
    }

    /** 
     * Determines whether the extension list (.jpg, .gif, etc) should 
     * show up in the human readable description. 
     * 
     * Only relevent if a description was provided in the constructor 
     * or using setDescription(); 
     * 
     * @see getDescription 
     * @see setDescription 
     * @see isExtensionListInDescription 
     */
    public void setExtensionListInDescription(boolean b) {
        useExtensionsInDescription = b;
        fullDescription = null;
    }

    /** 
     * Returns whether the extension list (.jpg, .gif, etc) should 
     * show up in the human readable description. 
     * 
     * Only relevent if a description was provided in the constructor 
     * or using setDescription(); 
     * 
     * @see getDescription 
     * @see setDescription 
     * @see setExtensionListInDescription 
     */
    public boolean isExtensionListInDescription() {
        return useExtensionsInDescription;
    }
}
